Protective apparatus for refrigerating systems



1950 A. POUKHALO-POUKHLOVSKY PROTECTIVE APPARATUS FOR REFRIGERATINGSYSTEIIS Filed Nov. 19, 1946 2 Sheets-Sheet 1 Alexis Ppukholo-Poukhlovsky.

ATTORNEY 23, 1950 A. POUKHALO-POUKHLOVSKY 2,532,074

PROTECTIVE APPARATUS FOR REFRIGERATING SYSTEMS Filed NOV. 19, 1946 2Sheets-Sheet 2 Fig.7o.

INVENTOR. Alexis Poukholo-Poukhlovsky. BY

ATTORNEY Patented Nov. 28, 1950 UNITED STATES- PATENT OFFICE PROTECTIVEAPPARATUS FOR REFRIG- ERATING SYSTEMS Alexis Poukhalo-Poukhlovsky,Paris, France, as-

signor of one-half to Konstanty P. Puchlowski,

Pittsburgh, Pa.

Application November 19, 1946, Serial In France November 22, 1945 20Claims.

It is, therefore, an object of my invention to provide an apparatuswhich automatically stops the operation of the system and confines therefrigerant as soon as a leak occurs in the system. As theabove-mentioned refrigerants are expensive, the value of such aprotective apparatus is evident.

With other refrigerants, such as sulphur dioxide or ammonia, a leak, asa rule, does not escape attention. However, a sudden break of a duit,preventing the attendants access to the valves and permitting largequantities of the charge to escape, can cause considerable damage.

It is, therefore, a more general object of my invention to provideapparatus which prevent refrigerants of any kind from escaping from arefrigerating system in appreciable quantities by confining therefrigerant in the receiver or other suitable vessel in response to theoccurrence of a relatively slight initial leakage or other anomaly.

In order to achieve these objects, and in accordance with one of thefeatures of my invention, I provide a protective apparatus which has avalve disposed at a suitable place of the refrigerating system, and Icontrol this valve by a sensing means that responds to changes in thedensity of the refrigerant, for instance, as caused by the occurrence ofgas bubbles in the refrigerant liquid. According to a more specificfeature of the invention, related to the one just mentioned, the densitysensing means comprises a float member of a buoyancy so chosen that itdescends in the liquid refrigerant in which it is located when theliquid suffers an appreciable change in density due to the gas inclusioncaused by a leak. According to another feature of the invention, thedensity sensing means comprises a body, for instance cup-shaped, that ismovably arranged in a vessel so as to form together therewith twochambers interconnected by an interstitial space so that the occurrenceof occluded gas or bubbles causes the sensing body to move.

According to another aspect of the invention, I provide level-responsivefloat means which respond to an abnormal drop in liquid level,preferably in the receiver or in a vessel communicating with thereceiver, and which effect a nonreversible control of a. normally openvalve so that the valve stops the flow of refrigerant upon occurrenceof. a leak or other abnormal condition.

According to another feature of my invention, I incorporate in theprotective apparatus a power transforming means so that a slight forceor torque produced by any of the above-mentioned sensing means sufiicesto control an appreciable force or torque acting on the valve controlledby the sensing means.

According to still another feature of the invention, I provide theprotective apparatus with a trigger type mechanism which acts on thevalve when released by the sensing means.

These and other objects and features of the invention will be apparentfrom the following description of the examples illustrated in thedrawing, in which:

Figures 1 to 4 show, in section, four different embodiments,respectively, of apparatus according to the invention;

Figs. 4a and 4b show, respectively, two modifications based on theembodiment of Fig. 4;

Fig. 5 shows, in section, a receiver vessel of special design to beconnected with apparatus such as shown in Fig. 3 or Fig. 4;

Fig. 6 represents a sectional view of a modification of apparatus suchas shown in Fig. 2;

Figs. 7, 7a and 8 are partial views of modified details to beincorporated in apparatus as shown in Fig. 6; and

Fig. 9 shows another modification of an apparatus according to theinvention.

The apparatus shown in Fig. 1 has a vertical vessel l whose inlet 2, atthe vessel bottom, is to be connected to the receiver of a refrigeratingsystem, while the outlet 3, at the top of vessel I, is to be connectedto the expansion valve (not shown) through which the refrigerant passesinto the evaporator (not shown), In normal operation, the refrigerantleaves the receiver as a liquid and remains in this state until itreaches the expansion valve. Hence, the refrigerant, normally fillingthe vessel l and travelling in the direction indicated by arrows, is aliquid. A float 4 inside the vessel I is so balanced relative to thedensity of the liquid, 1. e., has a buoyancy so chosen, that it justfloats under normal conditions. The float member 4 carries at its bottoma valve needle 5 which is engageable with a valve-seat 6. The valve thusformed is byby a conduit I which is normally closed by a valve 8. A stop9 is rigidly attached to the wall of vessel I and prevents the float 4from obstructing the opening of outlet 3.

The normal charge of the system is just suflicient to provide theminimum level (in the receiver) at which a normal supply of liquidrefrigerant to expansion valve or valves is secured. In consequence, theloss of a small quantity-of refrigerant from a correctly charged systemis sumcient to permit gas bubbles to enter into the liquid line. Incurrent practice, the presence of bubbles, visible in a sight glass, isthe first system of a shortage of refrigerant. Such a mixture of liquidand gas has a lower density than the pure liquid. Hence, when bubblesoccur, the float will sink,obstructing with the needle the inlet port.The compressor continuing to run or the refrigerant to escape, therefrigerant will be withdrawn from the vessel l, and the float 4 willpress down with its whole weight, thus causing the needle 5 to safelyclose the valve at seat 6. To again start the system, the valve 8 inby-pass i is opened until the vessel I is refilled.

One of the known pressure control devices (not shown) may be provided inorder to stop the compressor after the protective apparatus,above-described, has stopped the flow of refrigerant. It may happen, ifthe leak is relatively slight, that the compressor, before stopping andafter having emptied the evaporators, temporarily reestablishes thenormal level in the receiver. This however, has no eilect on theprotective apparatus which remains closed once a leak has been respondedto. This non-reversibility of action secures a high degree of safety andhence represents a considerable advantage.

In an apparatus according to Fig. 1, the port of valve seat 6 must havea sufflcient cross section to prevent too big a pressure drop.Therefore, in order to close the valve orifice by its weight, the floatmember 4 may have to be of inconveniently large size.

By modifying the construction of the apparatus, for instance as shown inFig. 2, this inconvenience can be avoided. According to Fig. 2, theliquid enters at 10, passes through an orifice into a valve chamber l2which communicates with the float chamber of vessel i3, and leaves atI4. A by-pass opening I5 is normally closed by a valve [6, and the samepressure, equal to the pressure of the condenser, exists on both sidesof a gas-tight and movable partition I! which is here shown as a bellowsbut may also consist of a diaphragm, piston or the like member. Thefloat I8, when descending, transmits its movement by means of a suitablelever means It, pivoted at 20, to a valve body 2|. A stop 22, rigidlyattached to vessel 13, limits the upward movement of float II.

In contrast to the embodiment of Fig. l, the float it according to Fig.2 does not provide the force to close tightly the oriflce H. It suflicesif the float closes the valve only partially so that the resultingthrottling action produces a slight pressure drop in the chamber l2. Theequilibrium of pressures on both sides of the bellows I! is thendisturbed, and the bellows I1 is caused to press the valve body 21against the oriflce ll. Consequently, the force that keeps the valveclosed, is no longer dependent on the weight of the float but dependsupon the ratio of the cross-sections of the orifice H and the partitionor bellows II. This force will be in- "vation of pressure in theevaporators has no disturbing effect on the tightness of the seal. Forstarting or restarting the system, the by-pass valve i6 is to betemporarily opened.

As a loss of refrigerant in the system is accompanied by a lowering ofthe level in the receiver, it is also possible to base the functioningof the protective device on this level variation. Fig. 3 shows such anapparatus.

In contrast to Fig. 2, the valve chamber 22 of the apparatus shown inFig. 3 is not in communication with the float chamber of vessel 23; andvessel 23 is not traversed by the liquid refrigerant. The float chamberis appropriately connected to the receiver by conduits 30 and 3| and theliquid in vessel 23 is on the same level as in the receiver.

In normal operation, the by-pass 25 is closed by a valve 26. The liquidenters through conduit 29, which is connected to the receiver, andpasses through the orifice 2| and leaves the apparatus at 24. If theliquid level goes down in the receiver, it will go down just as much invessel 23, and the float 28 will descend. This movement of the float istransmitted by an appropriate transmission through the movable and gastight partition or bellows 21 to the valve body 3! The partial closingof the valve disturbs the balance of pressures on both sides of thebellows 21 and the apparatus will then function like the one shown inFig. 2.

In apparatus, where the closing of the valve is caused by the variationof the liquid level, the non-reversibility of the closing movement isessential because, when the liquid supply line is once closed, thecompressor will pump gas from the evaporators to the condenser fromwhich the liquefied refrigerant reaches the receiver before beingstopped by the pressure control, and the level in the receiver willrise.

In apparatus according to the invention, regardless of whether theyrespond directly to density changes or to a change in liquid level, the

float-controlled valve mechanism can be designed as a trigger device sothat the movement of the controlling or sensing means is merely calledupon to release an auxiliary source of power. An example of this kind isshown in Fig. 4.

According to Fig. 4, the closing of the valve of the protectiveapparatus is executed by a springoperated power-storing device so thatthe float member during its descending movement has merely to release adetent or trigger. Such a device can be provided with springssufliciently powerful to alone insure the closing of the valve, but thevalve movement should remain non-reversible.

The apparatus shown in Fig. 4 has a vessel 33 with an inlet 34 and anoutlet at 35. Another conduit is shown at 36. The upward movement of thefloat 31 is limited by a stop 38 which is attached to the wall of vessel33. Conduits 34 and 36 are in communication with the receiver so thatthe liquid level in vessel 33 corresponds to that in the receiver, andthe float 31 is given enough buoyancy to keep it afloat regardless ofchanges in density.

The float 3! is mounted on a lever 39, pivoted at 40, which has atrigger extension 4 I. A normally compressed spring 42 biases a valvedisc 43 toward the appertaining valve orifice 44 but is normally heldinoperative by the trigger 4|. After the release of the triggermechanism by the descending float, the mechanism can be reset by pushinga pin 46, operable from the outside, toward the valve disc 43 so thatthe disc is moved upward until the detent or trigger 4| engages thevalve disc 43, provided thesystem has previously been recharged so thatthe vessel 83 is suilicientlv filled with liquid to lift the float. Ifdesired, and as also shown in Fig. 4, an electromagnet 48 may beprovided to reset the mechanism electrically. The magnet 46 has aplunger type core 4! connected by a rod 48 to the valve disc 43. Whenthe magnet 46 is energized, the core 41 moves upward and pulls the disc43 into locking position. Such a magnet may be used with all otherembodiments if desired. The setting of the spring-controlled mechanismcan be accomplished simultaneously with the opening of a bypass valveand in one operation by interconnecting both devices in a suitablemanner.

In all modifications of the invention, the descending movement of thefloat member can be utilized to vary the magnetic field of an outsidemagnet and to control an electrical device that will, for instance,close the liquid line or stop the compressor. This can be achieved, forinstance, in apparatus similar to the one shown in Fig. 4, if the device46, above referred to as an electromagnet, is designed as an inductancecoil which changes its inductive resistance when the core 41 changes itsposition due to the float-controlled release and closing of the valve.This change in inductance is then used for controlling theabove-mentioned electric devices (not shown) The electric devices shouldbe of non-reversible operation so that they are reset by the attendantwhen resetting the float mechanism. An embodiment of this kind is shownin Fig. 4a. The device D according to Fig. 4a is similar to that shownin Fig. 4 but modified in the manner just mentioned. The inductancevariations of the coil 46 control an electric relay circuit C to releasethe circuit breaker B of the compressor motor M thus stopping the motorwhen the float of device D closes the appertaining valve.

Apparatus according to the invention whose operation is based upon thevariation in liquid level stop the system every time the level becomesabnormally low, no matter what caused it, and thus not only protect therefrigerating system but also draw the attention to the existence ofanomalies, such as leaky expansion valves, loss of refrigerant,accumulation of the liquid in one evaporator, etc., that resulted in adisplacement of the refrigerant to the low side. Since an undueaccumulation of oil in the receiver may interfere with the normaloperation of level-responsive apparatus, an oil-separator (not shown) ofany commercially available type should be inserted between compressorand condenser in the known manner. An overcharge of refrigerant mayprevent this kind of apparatus from signalling the before-mentionedoperational anomalies; hence, the use of a visible liquid level or sightglass, such as shown at 32 in Fig. 3, is preferred.

To increase the sensitivity of the apparatus the interior cross sectionof the appertaining receiver can be diminished. For instance, Fig. 5presents a schematic cross-section of a receiver 49, inside of which amovable body 50 is placed approximately at the height of the lowestnormal operating level 5| or somewhat below that level. With the sinkingof the liquid below the limit level 5i, the float of the protectiveapparatus must begin todescend. The body 50 is attached to a movable rod52, operable from the outside. so that the body It can be adjusted toits Proper position. The receiver 48 is supplied with liquid refrigerantfrom the compressor (not shown) through the conduit 53 and has twoconduits I4 and II for connection to the protective apparatus, forinstance to conduits 30 and 8|, respectively, of the apparatus shown inFig. 3, or to conduits 34 and 38, respectively, of the apparatusaccording to Fig. 4. When the liquid level in the receiver 49 (Fig. 5)drops below the minimum level ii, the effect of the reduction in crosssection caused by the body 50 has the effect that small changes inquantity of liquid produce large level variations so that the protectivedevice has a correspondingly increased sensitivity.

The level-responsive protective device ac cording to the invention canbe placed inside the liquid receiver, especially if the characteristicsof the system are known in advance; in that case devices according tothe invention may have an apparent resemblance to the high-side floatcurrently used to control the feeding of refrigerant from the receiverto the evaporator; but aside from a different function, thecharacteristic irreversibility of the closing movement of theprotectiv'e apparatus distinguishes it essentially from such feedcontrol devices. An example of a receiver with a built-in protectivedevice according to the invention is shown in Fig. 4b. It will berecognized that this modification, in principle, is similar to the oneshown in Fig. 4.

The density of a liquid refrigerant depends on its temperature which,being a function of the condensation temperature, is variable. Hence,the density of the refrigerant may vary, for instance, between summerand winter, over a range dependent upon that of the ambient temperature.Therefore, in apparatus according to the invention as described so far,the float has sufllcient buoyancy to prevent the valve from closing atthe expected lowest density, 1. e. highest temperature of the liquid.This renders the apparatus less sensitive at lower liquid temperatures.However, such a change in sensitivity can be avoided by modifying theconstruction of the apparatus in the manner exemplified by Fig. 6.

The apparatus according to Fig. 6 is largely similar to that of Fig. 2and, therefore, the same reference numerals are used in both figures forcorresponding elements. However, in the apparatus of Fig. 6 the float I8of Fig. 2 is replaced by a cup-shaped container 58 which is open at thetop. The container 58 transmits its movement to the valve body 2| in thesame way as described above with reference to Fig. 2. The weight of thecontainer 58 is balanced in any appropriate way, for instance by aspring or, as shown, by a weight I58, so that the system rests inequilibrium and the valve orifice Ii is open when the apparatus isfilled and traversed by the liquid refrigerant. Innormal operation thecontainer 58 is filled and surrounded by liquid of equal density. Withthe occurrence of gas bubbles mixed with the liquid in the annular space51, the balance of the system is disturbed and the container 58 movesdownward and causes the valve to close.

In order to make the apparatus sensitive to the presence of a smallproportion of gas bubbles in the mixture, the annular space 51 must havea small cross section. To avoid an appreciable pressure drop that wouldcheck the downward movement of the container, it is possible to diaosams7 minish this cross section by restricting the pas sage only over asmall length as at I! in the upper part of the annular space 51.

As soon as the valve will close, the liquid contained in the apparatusbegins to evaporate. The container 58 should not be emptied more quicklythan the annular space 51, otherwise the container 5. would rise andoppose the closing of the valve by the movable partition ll. Care shouldalso be taken to have the apparatus ready for functioning as soon as thevalve ii of bypass opening I is opened, in. order to be sure that it isthe protective apparatus and not an obstruction in the refrigerantcircuit that causes the system to stop. In other words, when the systemis in operation, the container 58 should be filled rapidly and beemptied slowly.

One of the means for obtaining such a result is to provide the container58 with a cover as shown in Fig. 7. This cover 60 has two openings ofdifferent diameters; the larger opening I is closed by a valve disc 62pressed against the cover 60 by a spring 63. This valve permits therapid filling of the container 58 but will oppose itself to the emptyingof it. The container Bl will be emptied through the other, smalleropening 54, the diameter of which is chosen in such a way that theemptying of the annular space 51 (see Fig. 6) proceeds more quickly thanthat of the container.

Another way to obtain the same result would be to provide the cover 60with only one opening and to close that opening by a leakage valve sothat the valve presents less impedance to the influx than to the outfiuxof liquid. Such a modification is schematically shown in Fig. 7a.According to this figure, the cover 60 has only one opening 6| while thevalve member 52 has a leakage opening 64'.

Gas bubbles and oil present in the refrigerant circuit can possiblypenetrate into the container 58. If the oil is lighter than the liquidrefrigerant, it will be evacuated through the opening 84 (Fig. 7) If itis of the same density, its presence will not affect the working of theapparatus. Gas bubbles will leave the container through the same opening64.

In the case of oil heavier than the refrigerant, the construction of thecontainer 58 should preferably be altered as exemplified by Fig. 8.

According to Fig. 8, the modified container 58' has inside two tubes ofsmall diameter. The first tube 65 starts at the bottom of the container58', where oil may accumulate, and issues into the opening 64'. Tube 65serves the same purpose as opening 64 in the modification of Fig. '7.The second tube 66 communicates with the annular space 51 through anorifice 61 in the wall of the container 58' close to its bottom. Tube 86terminates close to the cover 50.

A pressure difference between spaces 68 and 68, due to the pressure dropin the annular space 51 and the narrow passage at 59, creates a currentin both tubes that causes the evacuation of oil.

Gas bubbles may penetrate in the container 58 at the moment when thesystem is started or through the tube 66. This gasv'vill' make thecontainer (including its contents) lighter so that container 5| rises.However, a stop in, firmly secured to vessel 58, then engages the valve62 and-prevents the valve from following the rising movement of thecontainer 58'. Hence, the valve opens and the gas will escape throughthe opening ll. As a result, the weight of the container 58' is restoredto its normal value so that the container sinks back to its normalposition. Density-sensitive apparatus according to the invention, in anyof the above-described embodiments and modifications, may be equippedwith a second by-pass conduit or duct, such as exemplified at H in Fig.6, which shunts the sensing member and the interstitial passage formedthereby. This by-pass (H in Fig. 6) extends between the chambers 68 and68 below and above the cup member 58 and may contain an exteriorlyoperable adjusting valve (not shown).

In cases where the diminution of the difference between the pressures ofthe high and low sides is not to be feared, it is possible, by placingthe valve on the side of the arriving liquid, to close it tightly by thedirect action of the float or floating container. This is schematicallyshown in Fig. 9. The apparatus illustrated in this figure is largelysimilar to that of Fig. 6 as will be recognized from the correspondingreference numbers. The flow direction of the liquid in Fig. 9 is denotedby arrows.

As is evidenced by the modifications shown and described, and as will beunderstood by those skilled in the art, my invention permits of variousmodifications and alterations other than those specifically disclosedwithout departing from the objects, principles and essential features ofmy invention and within the scope of the claims annexed hereto.

I claim as my invention:

1. Protective apparatus for refrigerating systems, comprising arefrigerant vessel having conduit means for connection to the system tobe protected, movable control means responsive to a refrigerantcondition and disposed in said vessel, a refrigerant control valveconnected to said control means to be controlled thereby in order tocontinuously prevent the flow of refrigerant in the system when saidcontrol means responds to a given abnormal value of said condition, andexteriorly actuable resetting means for said valve.

2. Protective apparatus for refrigerating systems, comprising a vesselfor refrigerant having conduit means for connection to the system to beprotected, valve means for controlling the flow of refrigerant in thesystem, density-responsive control means disposed in said vessel torespond to changes in density of the refrigerant, and means connectinsaid control means with said valve for controlling the latter to preventthe flow of refrigerant in the system when said density drops below agiven value.

3. Protective apparatus for refrigerating systems, comprising a. vesselfor refrigerant having conduit means for connection to the system to beprotected, valve means for controlling the flow of refrigerant in thesystem, density-responsive control means disposed in said vessel torespond to changes in density of the refrigerant, and

means connecting said control means with said a valve for closing saidvalve to prevent the flow of refrigerant in the system when said densitydrops below a normal value, and exteriorly actua'ble resettin means forcausing said valve to open.

' 4. Protective apparatus for refrigerating systems, comprising a vesselfor refrigerant having conduit means for connection to the system to beprotected, valve means for controlling the flow of refrigerant in thesystem, a fioat member movably disposed in said vessel and balancedrelative to the refrigerant-so as to descend in said refrigerant whenthe refrigerant density drops below a given value, and means disposedbetween said float member and said valve for .causing the latter toclose in response to descending movement of said float member.

5. Protective apparatus for refrigerating systems, comprising a vesselfor refrigerant having conduit 'means for connection to a system to beprotected, valve means for controlling the flow of refrigerant in thesystem, a float member movably disposed in said vessel and balancedrelative to the refrigerant so as to descend in said refrigerant whenthe refrigerant density drops below a given value, and means disposedbetween said float member and said valve for closing said valve toprevent the flow of refrigerant, and exteriorly actuable resetting meansfor opening said valve.

6. Protective apparatus for a refrigerant line, comprising a vesselhaving conduits for connection into the line, a member movably disposedin said vessel so as to change its position in response to an abnormalrefrigerant condition, a normally open valve for blocking therefrigerant line when the valve is closed, a power translating meansconnected with said valve for providing closing force for the latter andbeing controlled by said member .to apply said force when said floatmember moves in response to said condition, and separately controllableresetting means for opening said valve.

7. Protective apparatus for a refrigerant line, comprising a vesselhaving conduits for connection to the line so that said vessel isnormally traversed by refrigerant, a control member movably disposed insaid vessel so as to change its position in response to an abnormalrefrigerant condition, a normally open valve for blocking therefrigerant line when the valve is closed, a movable partition disposedin said vessel to separate therein two chambers for refrigerant, saidvalve being connected with said partition to be closed by movement ofsaid partition due to pressure dlifference between said chambers, andmeans actuable by said member to control said pressure difference so asto cause closing of said valve when said member moves in response tosaid condition.

8. Protective apparatus for a refrigerant line, comprising a vesselhaving conduits for connection to the line so that said vessel isnormally traversed by refrigerant, a control member movably disposed insaid vessel so as to change its position in response to an abnormalrefrigerant condition, a normally open valve for blocking therefrigerant line when the valve is closed, power means disposed to biassaid valve toward closing, a trigger mechanism normally preventing saidvalve from responding to said power means, said member being connectedwith said trigger mechanism to release said valve for closing inresponse to said condition, and separately controllable means forresetting said valve and said power means.

9. Protective apparatus for a refrigerant line, comprising a refrigerantvessel having conduits for insertion of said vessel in the high pressurezone of the line so that said vessel is normally traversed by liquidrefrigerant, a normally open valve in said vessel for blocking therefrigerant line when closed, movable control means in said vesselresponsive to an abnormal refrigerant condition for causing said valveto close upon occurrence of said condition, a by-pass shunting saidvalve and a separately controllable check valve disposed in said by-passand normally close ing the latter to permit opening said first valve byopening said check valve.

10. Protective apparatus for a refrigerant line, comprising arefrigerant vessel having an inlet conduit for connection to the highpressure side of the line and an outlet conduit for connection to theevaporator side of the line so that said vessel is normally traversedand filled by liquid refrigerant, a normally open valve disposed in saidvessel near said inlet conduit, movable control means in said vesselresponsive to an abnormal refrigerantcondition for causing said valve toclose upon occurrence of said condition, a by-pass shunting said valve,and a separately controllable and normally closed valve disposed in saidby-pass to permit opening said first valve by opening said second valve.

11. Protective apparatus for a refrigerating line, comprising a vesselhaving conduits for connection into the line at the high pressure sidethereof so that a given minimum level of liquid refrigerant obtains insaid vessel under normal refrigerant conditions, a float member disposedin said vessel and movable in response to changes in refrigerant level,a normally open valve controlled by said float member to close inresponse to occurrence of a level below said minimum to then prevent theflow of refrigerant in the line, and exteriorly actuable means forresetting said valve to open position.

12. Protective apparatus for a refrigerating line having a receiver forliquid refrigerant, comprising a vessel having two conduits forconnection to the receiver so that said vessel contains normally aquantity of liquid refrigerant above a given minimum level, a normallyopen valve for preventing the flow of refrigerant in the line whenclosed, a float member, disposed in said vessel to move in accordancewith changes in level and connected to said valve for controlling thelatter to close in response to the occurrence of a level below saidminimum, and separately controllable means for resetting said valve toopen position.

13. Protective apparatus for a refrigerant line, comprising a vesselhaving respective inlet and outlet conduits for insertion into the lineof the high pressure side thereof so that said vessel is normallytraversed by liquid refrigerant, a member disposed in said vessel so asto form together therewith an annular interstice and two chambers abovethe top side and below the bottom side respectively 'of said member,said member being balanced relatively to the refrigerant so as to moverelatively to said vessel when the difference in pressures in saidrespective chambers exceeds a given value, and a normally open valve forpreventing the flow of refrigerant in the line when closed, said valvebeing controlled by said member to close in response to movement of saidmember, and separately controllable means for resetting said valve toopen position.

14. Protective apparatus for a refrigerant line, comprising verticallyelongated vessel having an inlet conduit at its bottom and an outletconduit at its top for insertion of said vessel into the line at thehigh pressure side thereof so that said vessel is normally traversed byliquid refrigerant, a vertically elongated member movably disposed insaid vessel so as to form together therewith an annular interstitialspace and two chambers respectively located above the top side and belowthe bottom side of said member, said member being balanced relative tothe refrigerant so as i9 descend in said vessel when the difference 11of pressure in said two chambers exceeds a given value due to theoccurrence of gas bubbles, a normally open valve disposed for closingsaid inlet conduit under control by descending movement of said member,a by-pass fQr refrigerant shunting said valve, and a normally closedvalve disposed in said by-pass and separately controllable to open saidby-pass.

15. Protective apparatus for a refrigerating line, comprising a vesselhaving conduits for connection into the line at the high pressure sidethereof so that said vessel is normally traversed by liquid refrigerant,a cup-shaped member open at the top and movably disposed in said vesselso as to form together therewith an annular interstice and two chambersrespectively disposed above the top and below the bottom of said member,said member being substantially balanced so as to move relatively tosaid vessel in response to the occurrence of an abnormal pressuredifference between said chambers, and a normally open valve controlledby said member to close the line upon occurrence of movement of saidmember.

16. Protective apparatus for a refrigerating line, comprising a vesselhaving conduits for connection into the line at the high pressure sidethereof so that said vessel is normally traversed by liquid refrigerant,a cup-shaped member open at the top and movably disposed in said vesselso as to form together therewith an annular interstice and two chambersrespectively disposed at the top and bottom of said member, said memberbeing substantially balanced so as to move relatively to said vessel inresponse to the occurrence of an abnormal pressure difference betweensaid chambers, means covering the top of said member and having anopening and check valve means disposed for rapid filling and slowemptying of said member, and a normally open valve controlled by saidmember to close the line upon occurrence of movement of said member.

1'7. Protective apparatus for a refrigerating line, comprising a vesselhaving conduits for connection into the line at the high pressure sidethereof so that said vessel is normally traversed by liquid refrigerant,a cup-shaped member open at the top and movably disposed in said vesselso as to form together therewith an annular interstice and two chambersrespectively disposed at the top and bottom of said member, said memberbeing substantially balanced so as to move relatively to said vessel inresponse to the occurrence of an abnormal pressure difference'betweensaid chambers, means covering the top of said member and having twoopenings of diiferent cross section, a check valve disposed for closingthe larger arc of said opening so as to obstruct the discharge of liquidfrom said member through said larger opening while permitting theentrance of liquid into said member through said larger opening, and anormally open valve controlled by said member to close the line uponoccurrence of movement of said member.

18. Protective apparatus for a refrigerating line, comprising a vesselhaving conduits for connection into the line at the high pressure sidethereof so that said vessel is normally traversed by liquid refrigerant,a cup-shaped member open at the top and movably disposed in said vesselso as to form together therewith an annular interstice and two chambersrespectively disposed at the top and bottom of said member, said memberbeing substantially balanced so as to move relatively to said vessel inresponse to the occurrence of an abnormal pressure difference betweensaid chambers, means covering the top of said member and having anopening and a check valve disposed to reduce the flow of liquid fromsaid member while facilitating the flow of liquid into said member, astop disposed in said vessel to engage said check valve to open thelatter when said member is in said vessel beyond a given position, and anormally open valve controlled by said member to close the line uponoccurrence of movement of said member.

19. Protective apparatus for a refrigerating line, comprising a vesselhaving conduits for connection into the line at the high pressure sidethereof so that said vessel is normally traversed by liquid refrigerant,a cup-shaped member open at the top and movably disposed in said vesselso as to form together therewith an annular interstice and two chambersrespectively disposed at the top and bottom of said member, said memberbeing substantially balanced so as to move relatively to said vessel inresponse to the occurrence of an abnormal pressure difference betweensaid chambers, means covering the top of said member and having a checkvalve controlling said opening to obstruct the flow of liquid out ofsaid member through said opening while facilitating the flow of liquidthrough said opening into said member, a tube disposed in said memberhaving one open end near the bottom of said member and running to theoutside of said member through said covering means, a second tubedisposed in said member and having one end in communication with saidannular interstice and the other end extending close to said coveringmeans and in communication with the interior of said member, and anormally open valve controlled by said member to close the line uponoccurrence of movement of said member.

20. Protective apparatus for a refrigerating system, comprising arefrigerant vessel having conduit means for connection to the system tobe protected so that said vessel is normally traversed by refrigerant, acontrol member disposed in said vessel and movable in response to anabnormal refrigerant condition, a conduit communicating with said vesselso as to by-pass said member, a refrigerant control valve under controlby said member to prevent the flow of refrigerant in the system whensaid member responds to said condition, and separately controllablemeans for resetting said valve.

ALEXIS POUKHALO-POUKIEOVSKY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,947,574 Williams Feb. 20, 1934

